Patent GB-583679-A (GB)
Title: Improvements in and relating to apparatus for coating the inner walls of vitreous bulbs
IPC: H01J9/22
Filed: 1944-11-16
Abstract: <PICT:0583679/III/1> <PICT:0583679/III/2> Apparatus for coating the inner walls of a tubular bulb comprises a coating turret comprised of a header tank, rotatable about a vertical axis, for holding a coating fluid, and a plurality of outlet nozzles located in the bottom of the tank at regularly spaced points along a path about the axis of rotation thereof, a conveyer comprised of a plurality of heads each adapted to hold a bulb in a vertical position and means for advancing the heads into operative relation below the nozzles of the coating turret, thence along a portion of the rotative path of movement thereof and along an extended course of movements, an enclosure about the extended course of movement of the conveyer, and means for extending the conveyer and rotating the coating turret so as to cause the bulbs in succeeding heads of the conveyer first to be flushed by coating fluid discharged by a nozzle and then to be dried in the atmosphere within the enclosure.  Referring to the figures, the bulbs 15 are loaded into heads 16 of an endless conveyer 17 as it moves around the loading and unloading turret 18 and are internally coated as they pass about coating turret 19. Thereafter they are dried by movement back and forth along paths 20 to 27 within enclosure 28 and discharged at turret 18.  The <PICT:0583679/III/3> <PICT:0583679/III/4> <PICT:0583679/III/5> <PICT:0583679/III/6> bulb 15 is held in head 16 by a spring clip 29 and against stop 31, the head 16 comprising a vertical channel slide 32 supporting spring clip 29 and rests 30, and a channel shaped support 33 attached to conveyer chain 34 providing ways for the slide 32. The conveyer chain 34 passes around sprocket 35 at the loading turret and sprocket 351 at the coating turret.  The movement of heads 16 into contact with coating turret 19 advances bulbs 15 into position below the outlet nozzles 60 (Fig. 4), in the header 61 of the coating apparatus, the nozzles 60 of which both release the coating fluid from tank 61 and distribute it over the inner walls of bulb 15.  The nozzles 60 and header tank 61 move with the heads 16 as tank 61 is mounted on plates 62 carried by portion 63 of hub 361 holding sprocket 351.  When the conveyer 17 advances into the immediate vicinity of turret 19 the upper ends of bulbs 15 are below the plane of all parts of the nozzle 60, but as these paths converge, the roller 53 of the conveyer head 16 passes into a channel in cam 64 (Fig. 6) raising movable slide 32 and bulb 15 until the shoulder 65 (Fig. 4) is against the angular face of three pins 66 extending from the collar 67 and so positions the bulb 15 both vertically and centrally with respect to the nozzle 60.  At the limit motion the roller 53 is carried over on to the straight section 641 of the cam 64 which extends around the turret 19 to a corresponding point on the opposite side thereof.  When the conveyer head 16 advances the bulb 15 into engagement with the curved shoe 69 of the control finger 70 (Fig. 4), roller 78 engages and lifts push rod 79, hence moving lever 80 and so forcing pin 84 downwards against the spring 104 and allowing coating liquid to flow through nozzle 60 to bulb 15.  If no bulb is held in the head 16 this means does not operate.  The nozzle opening means 71 retains its relation with nozzle 60 as the turret 19 rotates, since it is mounted on plate 93 supported by posts 94 attached to plate 62.  When the nozzle operating means 71 is actuated and the pin 84 is moved down, the coating material flows from the header tank 61 through the orifice tube 102, through the opening in the orifice cap 100 and over the conical and skirted portion 106 and 109 respectively of the metering pin 84 to the walls of the bulb 15.  After the roller 89 (Fig. 8) passes from the end of cam 88 spring 891 turns arm 85 until stop screw 90 engages the back of bracket 87 returning metering pin 84 to its closed position.  The header tank 61 has a propeller 113 for agitating the coating fluid to prevent settling out of the fluorescent materials, and is fitted with automatic means for supplying additional coating fluid and so keeping the fluid level constant within the header tank.  The succeeding course of travel of the heads 16 of the conveyer 17 advances the roller 53 on the slide 32 thereof into a declining portion of the cam 64 which corresponds to that portion of the cam (Fig. 6) on the opposite side of the coating turret 19 and causes the slide 32 and the bulb 15 to be lowered from operative relation to the nozzle 60.  The subsequent period of travel of the head 16 allows the bulb to drain and the coating material to dry while moving around the enclosure 28.  Air may be circulated through the bulbs 15 while they are within enclosure 28.